Luckily my current contract isn’t up, so I can avoid the 4S temptation!
I’m aiming for the 5 myself... but there’s a BIG problem with that.
You see, 10-20 months later, the 5 will get a major internal upgrade, to a 5S, say... same shape, but a much better machine! Do I really want to get an iPhone 5, knowing something so much better is coming before my contract is even up? Plus, a second version of a proven design is likely to be even more refined and perfected (like the antennas on the 4S) vs. a brand-new design.
I say, wait for the iPhone 5S. Unless something better is coming after that, but I’ve heard no rumors about it if so...